USDA Forest Service

Pacific Southwest Research Station


Pacific Southwest Research Station
800 Buchanan Street
Albany, CA 94710-0011

(510) 559-6300

United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Research Topics Water and Watersheds

Study explores stream nitrogen concentrations

For the first time, a collaborative study [] has compared water quality trends in forested streams across the country that are largely undisturbed by land use or land cover changes. The study draws on 559 years of stream nitrate and 523 years of stream ammonium data from 22 streams in 7 experimental forests across the country. The study found that even near-pristine forested streams are subject to change.

Southern Sierra Critical Zone Observatory

The Kings River Experimental Watersheds hosts the Southern Sierra Critical Zone Observatory--a National Science Foundation effort to gain a better understanding of the zone of earth where "rock meets life." The critical zone extends from the tops of the trees to the groundwater and covers the entire earth where there is land. Dowload the video created by a UA Flandrau Science Center team to introduce the motivation and science involved in the National Critical Zone Observatory research program.

Kings River Experimental Watersheds (KREW)


A newly-built sediment catchment basin being filled at Bull 204 streamSediment loading in streams, particularly on small streams with large storm events, such as those in the KREW study, can be significantly affected by roads and other management activities. Gaining a better understanding of how treatments affect sediment is an important consideration for land managers, and an important component of KREW.

Sediment basins were built on seven of the KREW watersheds (a basin already existed at Teakettle) to quantify sediment coming off of each watershed. These basins are designed to slow down stream flow, which allows sediment to settle out at the bottom of the basin. Once a year, the basins are drained and the remaining sediment is manually removed and weighed to determine the previous year’s sediment load. A portion of the removed sediment is dried and processed in the laboratory to determine the amount of organic versus inorganic matter in the sediment. The specific protocol for this process, as well as dimensions and locations of basins, can be found in the KREW Study Plan (Hunsaker et al. 2004).

Sediment accumulated in a sediment fence for measurement of erosionInvestigations on stream headcuts and upland erosion provide information on the sources and processes that govern erosion. To supplement the data from sediment basins, KREW is collaborating with graduate students to quantify headcuts and their movement on KREW streams, and erosion in the upland from roads and hillslopes. These projects address topics that are important to land management in the Sierra, but not necessarily linked to logging or fuel-reduction activity. However, both projects are in their early stages and have yet to be refined. Also, as they are Master’s-level projects, each is not guaranteed to continue throughout the planned duration of KREW. For specifics about the sediment component, see the KREW Study Plan (Hunsaker et al. 2004).

Annual sediment production from five watersheds from 2002-2004

Last Modified: Jun 21, 2013 08:30:09 PM